Ophthalmic examination and conjunctival bacteriologic culture results from a herd of North American bison.

OBJECTIVE

To establish ocular characteristics, determine nature and prevalence of ocular lesions, and identify representative bacterial flora from the conjunctiva of North American bison (Bison bison).

DESIGN

Prospective study.

ANIMALS

63 bison; 45 males and 18 females.

PROCEDURE

Ophthalmic examinations were performed on 1 group of 38 bison in December 1997 and on a second group of 25 in March 1998. Eyes were examined with a penlight, magnification loop, and indirect ophthalmoscope. Two culture swabs were used to obtain samples from the inferior conjunctival sac. One swab was submitted for isolation of bacteria and the second was submitted for isolation of Mycoplasma organisms.

RESULTS

15 ocular abnormalities were observed in 13 of the 63 bison. These included minor ocular discharge in 5 animals, 1 eyelid laceration, 1 periocular Demodex spp infection, 6 corneal abnormalities, 1 anterior synechia, and 1 cataract. Seventeen species of bacteria were isolated from the 63 swabs submitted for culture. The most prevalent bacteria were of the genus Bacillus (74.6%). Mycoplasma organisms were not observed.

CONCLUSIONS AND CLINICAL RELEVANCE

Corneal abnormalities were the most frequently identified ocular lesions in bison. Bacterial flora of the conjunctiva and ocular characteristics were similar to those reported for cattle.